Cancer is a genetically complex and biologically heterogeneous group of disorders. It has become increasingly clear that the - laboratory mouse, the best genetically-defined experimental model organism for humans, presents a major opportunity for rapid advancement in understanding the genetic basis of cancer. Therefore, a broad-based training in mouse genetics, genomics and biology is critical to meet this end. The overall goal for our course is to train young scientists (predoctoral, postdoctoral trainees, new investigators) and to retrain established investigators in the use of genetically-defined laboratory mice as genetic tools for asking questions about gene function. Students completing the course will acquire working and critical knowledge of experimental approaches to: (1) Mouse genetics and genomics, (2) Mammalian development, (3) Mouse models for human diseases, (4) Ethical perspectives of genetic research. These Aims will be accomplished by offering an intensive 2-week course to 30 students chosen for their outstanding research potential. They will interact with a group of prominent mouse geneticists and biologists both from The Jackson Laboratory and other institutions. Student enrollment is kept deliberately small to achieve the desired high level of student-faculty interaction. The course is held in a retreat setting at Highseas, a Jackson Laboratory oceanfront conference center that is the site both for the course presentations and residential accommodations for the students and faculty. Lectures, workshops, and demonstrations are held mornings, afternoons, and evenings for a total of 87 hours of formal instruction. The Jackson Laboratory is an NCI-designated Basic Research Cancer Center and has a long history of presenting advanced courses and scientific meetings including the renowned "Short Course" co-organized with Johns Hopkins University and held here continuously for 37 years. The course on Experimental Genetics of the Laboratory Mouse described in this application has been held annually since 1992. The Principal Investigator and the Organizing Committee collectively have extensive experience in organizing and lecturing in Jackson Laboratory-sponsored and other courses and meetings.